Clarify that `CString::from_vec_unchecked` appends 0 byte.
/// Creates a C-compatible string by consuming a byte vector,
/// without checking for interior 0 bytes.
///
+ /// Trailing 0 byte will be appended by this function.
+ ///
/// This method is equivalent to [`CString::new`] except that no runtime
/// assertion is made that `v` contains no 0 bytes, and it requires an
/// actual byte vector, not anything that can be converted to one with Into.